Compressed natural gas is becoming trendy again in Argentina, as rising gasoline prices make it more economical, a shift that could help underpin the development of the country’s large shale gas resources and boost oil exports in the long term, an industry representative said Wednesday. More motorists are converting their cars to run on CNG this year after a three-year decline from nearly 240,000 in 2014, according to Enargas, the national gas regulator. The number of conversions rose 30% to nearly 30,000 in the first quarter of 2018 from about 23,000 in the year-earlier period, its data showed. The driver of the shift is the cost savings, said Pedro Gonzalez, vice president of the Chamber of CNG Retailers, an industry group.